Apparatus for producing readily openable plastic containers

ABSTRACT

The major portion of the raw edge (and adjacent areas) of the pouring spout of a plastic coated gable-top container is wet prior to heat sealing of the gable top and then the gable top is heat sealed to effect a liquidtight container closure. The wetting material, all or most of which should be a volatile liquid, coats the raw edge and penetrates the fibers of the coated stock. A wetting agent and/or a thickening agent is used to achieve wetting and to provide a coating of the wetting material on the raw edge and adjacent areas. The heat sealing step is performed promptly to avoid substantial loss of wetting material from the raw edge. The apparatus contacts the raw edge with a liquid-carrying member, e.g., a suitable sponge, which transfers the wetting material to the raw edge without dripping of wetting material into the container.

United States Patent inventors Appl. No. Filed Patented AssigneeAPPARATUS FOR PRODUCING READILY OPENABLE PLASTIC CONTAINERS 4 Claims, 9Drawing Figs.

U.S. C1 118/267, 53/37 Int. Cl. 1165b 7/18, B05c 1 1/10 Field of Search1 18/43. 267; 53/37 Primary Examiner-Louis K. Rimrodt Attorney-CharlesB. Smith ABSTRACT: The major portion of the raw edge (and adjacentareas) of the pouring spout ot' a plastic coated gable-top container iswet prior to heat sealing of the gable top and then the gable top isheat sealed to effect a liquidtight container closure. The wettingmaterial, all or most of which should be a volatile liquid, coats theraw edge and penetrates the fibers of the coated stock. A wetting agentand/or a thickening agent is used to achieve wetting and to provide acoating of the wetting material on the raw edge and adjacent areas. Theheat sealing step is perfonned promptly to avoid substantial loss ofwetting material from the raw edge. The apparatus contacts the raw edgewith a liquid-carrying member, e.g., a suitable sponge, which transfersthe wetting material to the raw edge without dripping of wettingmaterial into the container.

PATENTEBunv 30 m1 SHEET 1 0F 2 F'IG.4.

BACKGROUND OF THE INVENTION The present invention relates to the sealingof plastic coated containers and especially to such containers of thegable-top type which are to be heat sealed and which, when subsequentlyopened, afford a pouring spout.

A particularly good example of such a gable-top plastic coated containeris found in US. Pat. No. 3,292,842 which issued to Huang and Moors onDec. 20, 1966. Such containers are used in large quantities and areusually made from paperboard coated on both surfaces with polyethylene.A major advantage achieved by using containers made from paperboardcoated with polyethylene or other heat sealable plastic is that suchcontainers can readily be sealed against leakage by application of heatto polyethylene surfaces that are to be joined together, the heat actingto soften the polyethylene whereby when two strips of softenedpolyethylene are pressed together a liquidtight seal is formed.

One major difficulty which has been encountered in using polyethylenecoated containers, especially when used for beverages, is that the bondbetween heat-scaled surfaces is so strong that, when an effort is madeto open the container by pulling apart two or more such surfaces, thepolyethylene will be pulled away from the paper backing on one or theother of the surfaces, exposing a roughened paper surface to the actionofliquid as the container is used. Action ofliquid on the paper soonproduces an unsightly and unsanitary condition which is particularlyundesirable where a container is to be opened and tilted repeatedly indispensing the contents, as in the case of milk containers In makingpolyethylene coated paper mild cartons, heatsealing is usually effectedover limited areas in a definite complicated pattern to yield anoperable pouring spout. However, practical production problems preventlimitation of the heatsealing to only those areas which must be sealedfor a liquidtight container, and it is the additional areas which areundesirably heat-sealed which cause the greatest problem when the spoutis opened for dispensing liquid from the container.

The container of the aforementioned Huang and Moors patent greatlyminimizes the opening problem by providing an adhesive coating onselected areas of the container pouring spout. Nevertheless, thecontainer is sometimes not as easy to open as might be desired. Indeed,in some cases, the container may prove difficult to open. The easeofopening or top opening quality" of such a container is dependent on anumber of factors. The most important of these are the quality, filmthickness, and film uniformity of the adhesive material used to effectgood release, and the filling machine conditions of top heatertemperature, sealer jaw pressure, and the plowing" action of the sealerjaws on the carton spout as it enters the top sealer area. A poorquality adhesive application and/or high top heater temperatures andplowing" pressures exerted on the top ofthe carton during top closure,result in sticking of the spout end rib panels to the gabled roof ribpanels, especially at the spout rib panel raw edge, resulting indifficulty in top opening for the consumer.

The principal object of the present invention has been to provide anapparatus for sealing plastic coated containers which will render suchcontainers readily openable.

A particular object of the invention has been the provision of such anapparatus which are especially adapted to scaling gable-top plasticcoated containers in such a way that the container can readily be openedand the pouring spout extended.

Another object of the invention has been the provision of such anapparatus which will inhibit or eliminate sealing or sticking of thespout rib panels, and especially the spout raw edge, to the roof panelsduring top closure of the container, thereby improving top openingquality ofthe container.

SUMMARY The invention is concerned with a container sealing operation inwhich a container formed from plastic coated paperboard is to haveselected panels heated and forced together under pressure to effect aheat seal thereof, -the selected panels including at least one raw edge.Sealing of selected portions of the selected panels including andadjacent to the raw edge is inhibited by wetting the raw edge andadjacent portions forming the selected portions with a wetting materialto form a moisture film on the adjacent portions and to penetrate intothe paperboard fibers of the raw edge. The selected panels are then heatsealed before there is substantial loss of moisture from the raw edgeand adjacent portions.

The apparatus comprises an applicator box having an open bottom, acentral cavity communicating with the open bottom and a closed top. Thetop has an opening communicating with the cavity. A liquid resevoir isconnected to the cavity through a conduit. A porous, deformableapplicator pad is retained in the open end of the box and projectsdownwardly therefrom, this pad filling the open bottom so that liquidcan escape from the open bottom only through the pad. The systempreferably is nonvented so that liquid will not be lost from theapplicator pad unless the latter is deformed by contact with an objectto be wet.

BRIEF DESCRIPTION OF THE DRAWING The invention will now be described ingreater detail with reference to the appended drawing in which:

FIG. I is a perspective view illustrating one side of a container blankshowing the scoring lines and the inhibited or adhesive coated areas,the side illustrated in FIG. I being intended to be the outer surface ofa setup container;

FIG. 2 is a perspective view of the opposite side of the upper portionof the container blank of FIG. 1;

FIG. 3 is a perspective view illustrating one form of apparatusaccording to the invention positioned so as to operate on a setupcontainer blank in the practice of the method of the invention;

FIG. 4 is a top plan view of the applicator apparatus of FIG. 3positioned as in FIG. 3 and having portions broken away to show theinterior construction;

FIG. 5 is a cross-sectional view taken along the line 55 of FIG, 4;

FIG. 6 is a cross-sectional view line 6-6 of FIG. 5; and

FIG. 7 is a perspective view illustrating the container filled and withthe top partially closed;

FIG. 8 is a perspective view illustrating the sealed container partiallyopened; and

FIG. 9 is a perspective view illustrating the container fully openedwith the pour spout extended.

taken generally along the DESCRIPTION OF THE PREFERRED EMBODIMENTReferring now to the drawings, and more particularly to FIGS. I and 2,the carton is formed from a blank 20, which is a single integral sheetof paperboard coated on both sides with polyethylene. The cartondescribed below is essentially that of the Huang and Moors patentreferred to above and represents the construction in which the inventionis expected to find its principal, but not exclusive, utility. Thecoated board is cut and scored so that when the carton is formed itassumes the shape ofa rectangular container with a flat bottom and agable top.

FIG. 1 represents that surface of the blank which will become theoutside of the container, while FIG. 2 represents the upper portion ofthat surface which will become the inside of the container. A centralportion 21 of the blank between transverse score lines 22 and 23 becomesthe body of the container, Vertical score lines 24, 25, 26 and 27 dividethe blank into a side panel 28, a front panel 29, a side panel 30, arear panel 31, and a sealing panel or flap 32. Connected to and integralwith the lower edges of panels 28-32 are bottom closure flaps 33, 34,35, 36 and 37 respectively.

Integral with the upper ends of the panels 28-32 are top closure flaps38, 39, 40, 41 and 42, respectively. Those portions of the flaps 38-42beneath a transverse score line 43 define roof and end panels of thecarton top closure, while the areas above the score line 43 form anupwardly extending central rib in the container when setup and sealed.Panels 38 and become the gable roof panels, and projecting from thesepanels are panels 45 and 46, respectively, which form the sides ofcentral rib 44.

Diagonal score lines 47 and 48 define fold-back panels 49 and 50 frompanel 41. An upwardly projecting extension of panel 41 is divided by avertical score line 52 into inner rib panels 53 and 54. Diagonal scorelines 55 and 56 define foldback panels 57 and 58 from panel 39. Anupwardly projecting extension of panel 39 is divided by a vertical scoreline 59 into inner rib panels 60 and 61.

A diagonal score line 62 extending across panel 40 and partially acrosspanel 46 and a diagonal score line 63 extending across panel 38 andpartially across panel 45 are provided to facilitate spout opening, asis well known.

In forming the carton, a first step is to fold the blank lengthwisealong the score lines 25 and 27 so that the outside (FIG. 1) surfaceofflaps 32, 37 and 42 underlie the outer edge of the inner surface ofpanels 31, 36 and 41, respectively. Prior to bringing these surfacestogether, they should be heated to a polyethylene softening temperature,i.e., a temperature in the range of 250600 F. In this way the side seamof the carton will be formed by a polyethylenepolyethylene heat seal,affording a liquidtight sea]. This operation will normally occur at theblank-forming plant, and the side-sealed blanks will be shipped to thediary or other filling plant.

In accordance with the Huang and Moors patent referred to above, anadhesive coating is provided on selected polyethylene surface areasbefore the carton is heat-sealed. The coating may be applied byprinting, brushing or other technique, but is preferably applied byprinting during the blank-forming operation. If both the inside andoutside surfaces of the blank are to be provided with adhesive coatings,the printing may be effected on both sides simultaneously, or first onone side and then the other. In general, the adhesive coating will beapplied while the carton blank is being subjected to the usual printingoperation which is conducted to provide the desired advertising matteron the carton.

The polyethylene coated paper comprises a relatively stiff paperboardsheet coated on each side with a layer of polyethylene. The paperboardmight be, for example, 0.018 inch thick, the inner polyethylene layermight be, for example, 0.0011 inch thick, while the outer polyethylenelayer might be, for example, 0.00075 inch thick. Selected areas of thepolyethylene are supplied with an adhesive coating.

On the inner surface of the blank (Fig. 2) adhesive coatings 83, 84, 85and 86 (shown as stippled areas) are applied to portions of panels 45,61, 60 and 46, respectively. On the outer surface of the blank (FIG. 1),adhesive coatings 87 and 88 are applied to portions of panels 60 and 61.While it is considered preferable from a top-opening standpoint toprovide the adhesive coatings 87 and 88 on the outer surfaces of theinner rib panels 60 and 61, as shown, these coatings may be, and oftenare, omitted.

The adhesive coatings 84, 85, 87 and 88 should extend from the tops oftheir respective panels to the bottom of score line 43. Adhesivecoatings 84 and 88 should terminate a short distance from score line 25.Similarly, adhesive coatings 85 and 87 should terminate a short distancefrom score line 26.

Adhesive coatings 83 and 86 extend upwardly from the bottom of scoreline 43 to a maximum height such that the adhesive coatings are close tobut spaced from the top edges of panels 45 and 46, respectively. Thisminimum spacing from the top edges is preferably betweenthree-sixteenths inch and one-fourth inch, and the lateral location ofthis minimum spacing from score lines 25 and 26, respectively, is equalapproximately to the lateral length of the panels 60 and 61. The topedges of the coating areas 83 and 86 may be inclined downwardly from thepoint of minimum spacing toward the score lines 25 and 26, respectively,but at all points along these inclined edges the areas 83 and 86 extendabove the corresponding points of areas 84 and 85, respectively, sothat, when the carton top is heat-sealed, upper portions of adhesiveareas 83 and 86 will overlie each other. These upper portions are abovethe top edges of the panels 60 and 61.

The top edges of the coating areas 83 and 86 are also inclineddownwardly from the point of minimum spacing away from score lines 25and 26, respectively, to correspond to the shape of the rear walls ofthe pouring spout when the carton is fully opened. In this way thecarton may be opened and the spout formed without tearing the panels 45and 46 except along the upper edges and adjacent the score lines 25 and26. The spacing between adhesive areas 83 and 86 and score lines 25 and26, respectively, should be the same as that between these score linesand the adhesive areas 84 and 85. The spacing between the adhesive areas83 and 86 and score lines 24 and 27, respectively, is not critical andshould be sufficient to permit spout formation without tearing along therear edges of the areas 83 and 86.

The relationship between the various panels forming the container top isbest shown in FIGS. 7, 8 and 9. In FIG. 7 the container top is shown inthe process of being closed, the closing forces being indicated by thearrows 70 and 71. It will be noted that when the container top iscompletely closed, adhesive areas 87 and 88 will contact each other,adhesive areas 83 and 84 will contact each other, and adhesive areas and86 will contact each other. In FIG. 8 the container is shown partiallyopened, as by force exerted by the consumer along the arrows 74 and 75.In FIG. 9 the container is fully opened and the pouring spout isextended to permit pouring of the container contents.

The spout end rib panels 60 and 61 have raw edges 90 and 91,respectively, which are not coated with an adhesive material. Theseedges are formed in the die cutting operation in which blanks are cutout of a long web of polyethylene coated paper. As noted above, plowingpressures exerted on the top of the container during top closure tend toforce the spout end rib panel raw edges into bonding contact with thegable roof side rib panels. Thus the edge 90 tends to stick to side ribpanel 46 while the edge 91 tends to stick to side rib panel 45. In somecases the edges 90 and 91 may actually cut into the polyethylene coatingon the inner surfaces of panels 45 and 46. Sticking of the end rib paneledges 90 and 91 and the adjacent side portions of the end rib panels 60and 61 to the side rib panels is more likely to occur and to providedifficulty in top opening if the adhesive application is in any wayfaulty, as sometimes occurs in the high speed printing necessary forblank production, or if the top heater temperatures of the dairy fillingand sealing machine are too high, as some times occurs even in carefullycontrolled dairy operations.

In accordance with the invention, sealing or sticking of the spout endrib panels, and especially their raw edges and adjacent surfaces, to thespout side rib panels is eliminated or greatly reduced by wetting ormoistening the spout end rib panel raw edges 90 and 91 and adjacentportions of the end rib panels on both the inside and outside of thecontainer. The wetting should be effective across the width of the rawedges 90 and 91 except for the portions near the adjacent side ribpanels 46 and 45, respectively. The width of the portions not wet ispreferably equal to the width of those portions of end rib panels 60 and61 not covered by adhesive areas 85 and 84, respectively. Typically theadhesive areas, and hence also the wet areas, will extend to aboutthree-eighths inch from the respective score lines 25 and 26 for a quartsize container and to about five-eighths inch for a gallon sizecontainer.

The polyethylene, adhesive and paperboard along the raw edges 90 and 91should all be wet, except adjacent score lines 25 and 26. The moistureshould also penetrate into the paperboard itself by wicking action,preferably to a depth of about one thirty-second inch to one-eighthinch, and should coat the adhesive along the inside and outside surfacesof the end rib panels for a substantial height, e.g., one-eighth inch toonefourth inch or more. Where the adhesive is omitted from the outersurfaces of the end rib panels, which is the usual commercialconstruction, the polyethylene surfaces will be wet instead.

The wetting material should be one which will penetrate into thepaperboard fibers at the raw edges and which will coat the adjacentadhesive or polyethylene surfaces. All or at least a major portion ofthe wetting material should be volatile at the heat sealing temperaturesemployed in effecting the container top seal. Usually heat sealing willbe effected at 250 F. or above, but polyethylene can be heat sealed topolyethylene at temperatures as low as 21 5220 F.

The preferred wetting material in water containing a wetting agent whichwill facilitate water penetration into the paperboard fibers and whichwill form a film of water on the polyethylene and adhesive surfaces towhich it is applied. Both anionic and nonionic wetting agents have beentested and found satisfactory in the practice of the invention.

Typical examples of suitable wetting materials are set forth in thefollowing examples in which percentages are by volume:

Distilled Water 98.0 99.0

While the use ofa wetting agent is preferred in the practice of theinvention, a thickening agent may be used to provide the coating ofwetting material on the polyethylene and adhesive surfaces and to permitpenetration of moisture into the paper fibers through the raw edges.Examples of such thickening agents usable with water are ethylcellulose, carboxy methyl cellulose, gelatin, starch and the highermolecular weight Methocel formulations.

Where the container is intended to hold a food product it is, of course,important that the wetting materials be nontoxic. Such materials shouldbe selected to conform to FDA and local health authority regulations.

The quantity of wetting material applied may be varied over aconsiderable range. The maximum quantity which may be applied is fixedby that quantity at which inadequate top sealing is achieved. In atypical container of the type illustrated in a one quart size, the rawedges 90 and 91 may each be 1% inch long but only about 1 inch of eachwill be wet. The preferred quantity of wetting material for such acontainer has been found to be about 0.04 to 0.1 cc. per quartcontainer. The 0.1 cc. quantity of wetting material referred tocorresponds to about 3.12 cc. per square inch of raw edge surface.

It has been found preferable to apply the wetting material to thecontainerjust prior to the container top sealing operation. If any greatdelay occurs between the application of the wetting material and the topsealing operation, the loss of wetting material through evaporation orother causes will reduce the level of top opening improvement achieved.By way of example, a time lag of 25 seconds between application of thewetting material and entry of the container into the top heater whichheats the polyethylene for top sealing was found to yield a good topopening quality. On the other hand, a time lag of 54 seconds duringwhich the container was exposed to the bottom heaters which form thebottom seal was found to result in no noticeable top opening qualityimprovement, i.e., the wetting did not result in any improvement over asimilar container with no wetting. It is not the time lag as such whichresults in poorer performance but rather exposure of the container overa period of time to conditions in which substantial wetting material islost. Should it be desired to wet the container a substantial timebefore top sealing, some technique such as microencapsulation of thewetting material should be used to prevent loss of moisture.

A number of factors are believed to result in top opening qualityimprovement from the wetting of the end rib raw edges and adjacentareas. One of these factors is a cooling of the end rib panel raw edgesby contact with a relatively cool liquid which must be heated to theboiling point during the polyethylene heat sealing operation. Anotherfactor is the evaporation of volatile material, e.g., water, during theheat sealing operation and the consequent cooling of the surfaces fromwhich the volatile material is evaporated. Still a further factor is thelubricating eflect produced by moisture on the raw edge areas as theseedges are forced into engagement with the side rib panels and bymoisture on the adjacent surfaces of the end rib panels as they moveinto surface contact with the side rib panels.

It has been found that penetration of the liquid into the paperboardfibers is important in achieving good top opening improvement and thatit is not satisfactory merely to coat the side surfaces of the end ribpanels without also wetting the raw edges themselves and achievingpenetration of liquid into the paperboard fibers.

In FIG. 3 there is shown the upper portion of a container formed from ablank 20. The container 100 in FIG. 3 is assumed to have been set up andto have had the bottom seal formed. The setting up and bottom sealingmay be effected in any of the well-known machines made for this purposeand which are installed and operating in dairies throughout the world. Atypical machine of the type employed by dairies to set up, fill and sealplastic coated paperboard containers is shown and described in US. Pat.No. 3,120,089 to Monroe et al. issued Feb. 4, 1964.

The container 100 of FIG. 3 is shown in contact with a top wettingdevice indicated generally by the reference numeral 101. The device 101is shown in greater detail in FIGS. 4-6 and comprises an applicator box102, an applicator pad 103,21 top plate 104, a face plate 105, asupporting arm 106, a feed tube 107 and a reservoir 108 (FIG. 3).

The box 102 may be formed from a molded plastic and may be in one piece,two pieces or three pieces, as shown. The upper piece 109 of box 102 hasa central cavity 111 which is rectangular in the cross section of FIG. 6and trapezoidal in the cross section of FIG. 5. The top wall of thepiece 109 has a central opening which accommodates the threaded end oftube 107 so that liquid from reservoir 108 will flow through tube 107into cavity 111. The bottom of cavity 111 communicates with hollow lowerpiece 110 of box 102. The piece 110 has sidewalls 112, 113, and 114. Thebottom wall of 116 of upper piece 109 around cavity 111 forms the topclosure for bottom piece 110. The top edges of walls 112, 113, and 114may be affixed adhesively to the bottom wall 116 of top piece 109. Thewall 116 has an opening corresponding in size and shape to the openbottom of cavity 111. The wall 116 may be provided with an integralcentral stiffening bar portion 117 (FIG. 5). The side wall 114 isprovided with inwardly extending bottom flange 118 (FIG. 6). Acorresponding flange number 119 is provided at the other side of box102. The flange number 119 may be adhesively affixed, as shown, to acork gasket 122.

Approximately one-half of applicator pad 103, which is preferably asynthetic sponge, is accommodated in the opening of bottom piece 110.The remainder of pad 103 extends below the bottom of box 102. The pad103 is preferably T- shaped in cross section and is slightly larger inlength and width than the corresponding dimensions of the hollow openingof bottom piece 1 so that the pad must be compressed in both length andwidth to be fitted into that opening. Flanges 118 and 119 extend intothe sides of pad 103, as best shown in FIG. 6, to form a narrow waist inthe pad 103. By reason of the compression of pad 103 the top thereof maybow slightly and extend into cavity 11 1.

Top plate 104, which is spaced from applicator box 102 by arm 106, isattached to the top piece 109 of box 102 by machine screws 120 and 121acting in openings in top plate 104 and threaded holes in top piece 109.Both top plate 104 and arm 106 have holes which accommodate tube 107.Both the top plate 104 and the arm 106 are preferably made of stiffmetal, e.g., steel. Face plate 105, which is preferably plastic, isspaced from the sidewall of applicator box 102 by cork gasket I22.Machine screws 123 and 124 which act in holes provided in face plate 105and gasket 122 are threaded in holes provided in top piece 109 to holdface plate 105, flange member 119 and gasket 122 in place. With faceplate 105, gasket 122 and flange member 119 removed, pad 103 is readilyinsertable in hollow bottom piece 110.

Arm 106 is attached to a suitable supporting member (not shown) on thecontainer filler and sealing machine (not shown) or other machine withwhich the unit is associated so that at a preselected point in themotion of the container through the machine the panels 60 and 61 arebrought into contact with the bottom surface of pad 103 anddeform thepad in a substantially U-shaped cross section, as shown in FIGS. 3 and6. Deformation of the pad 103 may be effected by moving the top wettingdevice 101 into contact with a container or by moving the container intocontact with the top wetting device. In either case the motion involvedis preferably a reciprocating motion in a vertical direction.

One desirable place for locating the applicator device is adjacent thetop breaker unit of the filling and sealing machine. The top breakerunit, as is well known in the art, acts to break the container top alongits score lines so that the container top will be ready to be heatsealed. In the usual machine, after a container bottom is formed andsealed,the container is transferred to an indexing conveyor. At onepoint in the conveyor, termed the container locator section, as the topbreaker unit moves downward to break the top of the container thecontainer locator unit moves downwardly to position accurately thepreceding container on the conveyor. By attaching the applicator device102 to the container locator support arm and positioning the applicatordevice correctly, when the top breaker unit comes down to break acontainer, the preceding container on the conveyor will be contacted bythe applicator unit, as shown in FIGS. 3-6. When the top breaker unitreciprocates upwardly after completion of top breaking, the applicatordevice likewise will reciprocate upwardly. The container with its wettedsurfaces will then advance to the top breaker section where its top inturn will be broken. The container, with the wetted surfaces and brokentop score lines then moves on to the filling section, the top heater andthe sealer, as is well known in the art.

The pad 103 is preferably an artificial sponge, but may be a felt pad.Specific examples of satisfactory artificial sponges are 80 and 100pores per lineal inch polyurethane foams having densities of4 pounds percubic foot.

The reservoir 108 should be located above the applicator pad so that thetubing I07 and cavity 108 are kept filled with the wetting liquid. Theliquid will thus be in direct contact with the applicator pad and willsaturate that pad. Since the liquid flow system is nonvented, no liquidwill drip from the applicator pad. However, when the carton raw edgecontacts the applicator pad, a volume of liquid will be transferred tothe raw edge of the container lip (including adjacent side surface ofthe end rib panels). A volume of liquid equal to that transferred will,upon removal of the container. flow from the reservoir 103 to the pad102.

When the container, with its wet raw edge, reaches the top heatersection the top portions of the container are subjected to heat tosoften the polyethylene in certain portions of the top of the container,as is well known in the art. However, heat reaching those portions whichpreviously have been moistened, as described above, will be absorbedprimarily by the wetting material and will be used in volatilizing thevolatile portions of the wetting material. As a result the polyethyleneand/or paperboard in such moistened areas will stay below thetemperatures required to effect a polyethylene to polyethylene orpolyethylene to paper seal. The wetting material also acts as a barrierbetween otherwise sealable surfaces, inhibiting sealing in such areas.By inhibiting polyethylene to polyethylene and/or polyethylene topaperboard seals, severe sticking or sealing of the spout end rib panelsto the side rib panels is reduced or eliminated as the container passesthrough the top sealer section of the filling and sealing machine.Subsequent top opening of the container is thereby facilitated.

The top wetting, when combined with adhesive application, has been foundto produce a superior container from a top opening standpoint, and isparticularly useful in those cases where the adhesive coating, for onereason or another, is itself unable adequately to inhibit sealing.

The nonvented gravity feed applicator device illustrated in FIGS. 3-6may be made a vented system, as by providing an opening in reservoir 108for the entry of air. In such case a needle valve may be placed at someconvenient point between the reservoir and the applicator pad to meterthe flow of liquid to the pad so that it is equal to the volume ofliquid removed by the container raw edge. Such a needle valveconveniently might be operated by contact with an edge of the container.More sophisticated feed systems such as a timed flow through a smallorifice or intermittent use ofa valve can also be used.

The invention has been described primarily in connection with agable-top container having an extensible pouring spout since it is withthat type of container that the principal utility of the invention ispresently anticipated. However, it should be understood that theinvention will be found useful in other contexts. Hence, while theinvention has been described primarily in connection with specific stepsand in specific embodiments thereof, various modifications will occur tothose skilled in the art without departing from the spirit and scope ofthe invention as set forth in the appended claims.

What is claimed is:

1. Apparatus for wetting a narrow edge and adjacent side portions of athin panel, comprising an applicator box having an open bottom, acentral cavity communicating with said open bottom, a closed top, saidtop having an opening communicating with said cavity and flange meansprojecting inwardly from the sides ofsaid box adjacent the bottom edgesof said sides to close partially said open bottom and form between saidflange means a restricted neck; a liquid reservoir, conduit meansinterconnecting said reservoir and said top opening so that liquid fromsaid reservoir will fiow into said cavity, a generally T-shaped porousdeformable applicator pad retained in said open bottom of said box andhaving the narrow portion thereof projecting through said neck andbeneath said open bottom, said pad filling said open bottom so thatliquid can escape from said open bottom only through said pad, thethickness of said narrow portion of said pad being greater than thewidth of said neck so that the edges of said flange means deform saidnarrow portion of said pad at said neck, said pad being adapted to becontacted by said narrow edge of said panel and to be deformed therebyto wet said narrow edge and adjacent side portions of said panel.

2. Apparatus as set forth in claim 1 in which the liquid path includingsaid reservoir, said conduit means and said applicator box are notvented.

3. Apparatus as set forth in claim 1 in which said applicator pad is asynthetic sponge.

4. Apparatus as set forth in claim 3 in which said sponge is apolyurethane foam.

Col

Col

I atent No.

Inventor(s) UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION DatedNovember 30,

It is certified that error appears in the above-identified patent lineline line line line line line line line line line line line line lineline line line line line line line line line line line line line lineline and that said Letters Patent are hereby corrected as shown below:

26 "heat-scaled" should be heat-sealed 47 "adhesive" should be abhesive53 "adhesive"should be ab esive 57 "adhesive" should be abhesive 32"adhesive" should be abhesive 36 "adhesive"should be abhesive 4L"adhesive" should be abhesive 43 "adhesive" should be abhesive 53"adhesive" should be abhesive 54 "adhesive" should be abhesive 57"adhesive" should be abhesive 59' "adhesive" should be abhesive 63"adhesive" should be abhesive 65 --"adhesive" should be abhesive 66"adhesive" should be abhesive 67 "adhesive" should be abhesive 69"adhesive" should be abhesive 70 "adhesive" should be abhesive 7"adhesive" should be abhesive l7 "adhesive" should be abhesive l9"adhesive" should be abhesive 20 "adhesive" should be abhesive 29"adhesive" should be abhesive 30 "adhesive" should be abhesive 31"adhesive" should be abhesive 38 "adhesive" should be abhesive 51"adhesive" should be abhesive 66 "adhesive" should be abhesive 67"adhesive" should be abhesive 72 "adhesive" should abhesive )RM F o-105G10-69 Page 2 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIONlatent No. 3,623,452 Dated November 3-0, 1971 Harold B. Moors'andFrederick E. Bichavlo Inventor(s) It is certified that error appears inthe above-identified patent and that said Letters Patent are herebycorrected as shown below:

Col. 5 line 2 "adhesive" should be abhesive line 4 "adhesive" should beabhesive line 10 "adhesive" should be abhesive line 19 "adhesive" shouldbe abhesive line 27 after Minimum insert Maximum line 40 under ExampleNo. 4 Distilled Water, insert under Maximum --99.0;

line 41 delete 99.0:

line 46 "adhesive" should be abhesive Col. 8 line 20 "adhesive" shouldbe abhesive line 23 "adhesive" should be abhesive Signed and 'sealedthis 27th day of June 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOT'I'SGHAIK Attesting 'Officer 0Commissioner of Patents

1. Apparatus for wetting a narrow edge and adjacent side portions of athin panel, comprising an applicator box having an open bottom, acentral cavity communicating with said open bottom, a closed top, saidtop having an opening communicating with said cavity and flange meansprojecting inwardly from the sides of said box adjacent the bottom edgesof said sides to close partially said open bottom and form between saidflange means a restricted neck; a liquid reservoir, conduit meansinterconnecting said reservoir and said top opening so that liquid fromsaid reservoir will flow into said cavity, a generally T-shaped porousdeformable applicator pad retained in said open bottom of said box andhaving the narrow portion thereof projecting through said neck andbeneath said open bottom, said pad filling said open bottom so thatliquid can escape from said open bottom only through said pad, thethickness of said narrow portion of said pad being greater than thewidth of said neck so that the edges of said flange means deform saidnarrow portion of said pad at said neck, said pad being adapted to becontacted by said narrow edge of said panel and to be deformed therebyto wet said narrow edge and adjacent side portions of said panel. 2.Apparatus as set forth in claim 1 in which the liquid path includingsaid reservoir, said conduit means and said applicator box are notvented.
 3. Apparatus as set forth in claim 1 in which said applicatorpad is a synthetic sponge.
 4. Apparatus as set forth in claim 3 in whichsaid sponge is a polyurethane foam.